Washington -LRB- CNN -RRB- -- Republicans ' chances of winning control of the Senate in Tuesday 's midterm elections are now up to 95 % , according to CNN 's Pivit , an analysis that combines experts ' projections with political watchers ' predictions on key races .

The jump was driven largely by a Des Moines Register poll over the weekend that put Republican Joni Ernst 7 percentage points ahead of Democrat Bruce Braley in a Senate race seen as a must-win for Democrats .

In that race , Pivit puts Ernst 's chances at 88 % . Pivit also offers bad news for Democratic Sen. Mark Udall in Colorado , whose chances are at just 6 % , and Sen. Mark Pryor in Arkansas , who 's down to 2 % .

Pivit 's analysis suggests Democrats are in better shape in North Carolina , where Sen. Kay Hagan has a 69 % chance of holding off Republican challenger Thom Tillis , and in New Hampshire , where Sen. Jeanne Shaheen 's chances of beating Scott Brown are up to 81 % .

Republicans , meanwhile , look to have put Kentucky 's Senate race out of reach . Senate GOP leader Mitch McConnell 's chances of surviving a challenge from Democrat Alison Lundergan Grimes are up to 97 % .

Republicans need a net gain of six seats to capture a majority . Pick-ups in Montana , South Dakota and West Virginia are all but assured , and Democratic incumbents are facing uphill battles in Alaska , Arkansas and Louisiana , as well .

Republicans are also hoping for wins in states like Colorado , Iowa , New Hampshire and North Carolina -- which would help solidify their chances of gaining a majority by providing insulation in case the GOP loses seats of its own in Georgia and Kansas .

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After rosy polls , CNN 's Pivit puts Republicans ' chances of winning a Senate majority at 95 %

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Pivit gives the GOP strong odds of picking off Democratic seats in Iowa , Colorado and Arkansas

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Democrats could hold seats in North Carolina and New Hampshire , the analysis suggests